A differential combiner circuit (200) comprises three ports each has two terminals (1a, 1b, 2a, 2b, 3a, 3b). The differential combiner circuit (200) further comprises a first sub-circuit comprising a first inductor (L1) connected between the first terminals (1a, 2a) of the first and second ports, and a first capacitor (C1) connected between the first terminals (2a, 3a) of the second and third ports; a second sub-circuit comprising a second inductor (L2) connected between the second terminals (1b, 2b) of the first and second ports, and a second capacitor (C2) connected between the second terminals (2b, 3b) of the second and third ports. The differential combiner circuit (200) further comprises a third capacitor (C3) connected between the first and second terminals (1a, 1b) of the first port, a third inductor (L3) connected between the first and second terminals (3a, 3b) of the third port; a first resistor (R1) connected between the first terminal (1a) of the first port and the second terminal (3b) of the third port; and a second resistor (R2) connected between the second terminal (1b) of the first port and the first terminal (3a) of the third port.